The present invention relates to a voltage control circuitry for a detection cell, to a current control circuitry for a detection cell, and to a separation system. The invention further relates to a method for determining an electrical property of a sample.
A detection cell, like e.g. a contactless conductivity detection (CCD) cell, is adapted for analyzing an electrical property of a fluid sample. A detection cell might e.g. be part of a flow path, in order to detect various compounds of a fluid sample. When designing a detection cell, the aim is to arrive at a good resolution of the obtained spectra or record, and to reduce the limit of detection (LOD), which is a measure of the minimum concentration required for detecting a certain compound.
For detecting a respective electrical property, a voltage is applied across the detection cell volume. In prior art solutions, it has been attempted to improve the measurement accuracy by keeping the applied voltage as constant as possible. Or, if that is difficult, it's variance is compensated for the read-out. For example, the Czech patent CS Certification AO 270085 dealing with “auto-calibration principle” was registered in 1991. The voltage of the generator is evaluated and serves as a reference voltage to correct the read-out.